The present disclosure relates to techniques for performing oilfield operations. More particularly, the present disclosure relates to techniques for performing wellbore stimulation operations, such as perforating, injecting, treating, fracturing and/or characterizing subterranean formations.
Oilfield operations may be performed to locate and gather valuable downhole fluids, such as hydrocarbons. Oilfield operations may include, for example, surveying, drilling, downhole evaluation, completion, production, stimulation, and oilfield analysis. Surveying may involve seismic surveying using, for example, a seismic truck to send and receive downhole signals. Drilling may involve advancing a downhole tool into the earth to form a wellbore. Downhole evaluation may involve deploying a downhole tool into the wellbore to take downhole measurements and/or to retrieve downhole samples. Completion may involve cementing and casing a wellbore in preparation for production. Production may involve deploying production tubing into the wellbore for transporting fluids from a reservoir to the surface.
In some cases, stimulation operations may be performed to facilitate production of fluids from subsurface formations. Such stimulations may be performed by perforating the wall of the wellbore to create a flow path to reservoirs surrounding the wellbore. Natural fracture networks extending through the formation also provide pathways for the flow of fluid. Man-made fractures may be created and/or natural fractures expanded to increase flow paths by injecting treatment into the formation surrounding the wellbore.
Certain downhole parameters may affect stimulation operations. Oilfield analysis may be performed using such downhole parameters to characterize and understand downhole conditions. In some cases, oilfield analysis may involve deploying downhole tools into the wellbore to measure downhole parameters, such as temperature and pressure, or to perform various downhole tests, such as minifracs, microfracs and Diagnostic Fracture Injection Tests (DFIT). The resulting information may be analyzed to characterize downhole conditions which may affect stimulation and/or production. Examples of downhole analysis are provided in U.S. Pat. No. 6,076,046; K. G. Nolte, “Background for After-Closure Analysis of Fracture Calibration Tests”, (SPE 39407), Unsolicited companion paper to SPE 38676, July 1997 (referred to herein as “SPE 39407”); Jean Desroches et al., “Applications of Wireline Stress Measurements” (SPE 58086), SPE ATCE, New Orleans, La., USA, 27-30 Sep. 1999 (referred to herein as “SPE 58086”); Bryce B. Yeager et al., “Injection/Fall-off Testing in the Marcellus Shale: Using Reservoir Knowledge to Improve Operational Efficiency”, (SPE 139067) SPE Eastern Regional Meeting, Morgantown, W.Va., USA, 12-14 Oct. 2010 (referred to herein as “SPE 139067”); and R. D. Baree et al., “Holistic Fracture Diagnostics: Consistent Interpretation of Prefrac Injection Tests Using Multiple Analysis Methods,”(SPE 107877) SPE Vol. 24, No. 3, August 2009 (referred to herein as “SPE 107877”), the entire contents of which are hereby incorporated by reference. Some rock formations, such as shale, may pose difficulties in performing certain downhole measurements and/or characterizations.